Welcome to Apnea Board ! As a guest, you are limited to certain areas of the board and there are some features you can't use. To post a message, you must create a free account using a valid email address.
Login or Create an Account

No expert at all here. Only about three months in myself but do research things alot including here.

I read that there is such a thing as pressure induced centrals. My own experience has been that I do flag a few once in a while but they almost never coincide with a pressure increase on my auto machine. And at the lab nor the home test did I show any CAs even with higher pressures at the lab than my max is now.

So at least the little I know is that yeah you can induce some folks to have CAs with to much pressure, but it seems like even about all of those of us that dont have Central Apnea will have their machine flag a CA or even a few once in a while.

In brief - yes. Pressure above your titrated range can induce central apnoeas, however, the risk of centrals has to be weighed against the overall benefit, should the higher pressure reduce the overall AHI. Also, a few CA events over the night is statistically meaningless, especially if the events are of short duration.

In response to SurferDude, the machine can mistake a skipped breath or a swallow when awake as an event, mostly because we can and do breathe occasionally with greater gaps between inhalations when awake, mostly either when swallowing mucus, preparing to cough, concentrating or experiencing arousal (the waking phase, not the ....other... thing). Examining your readouts on Sleepyhead, if you notice the bulk of your events are occurring either in the first 30 minutes of your putting on your mask or in the waking phase in the morning, or if our sleep is momentarily disturbed by some outside source (in my case, my wife, who gets up before me, opening the cupboard to get her clothes), although these are counted within your AHI and even counts, if there is no other cluster of events during the main sleep phase, these can safely be ignored.

(11-18-2014, 08:25 PM)TyroneShoes Wrote: This seems to be what I might have heard. Still fuzzy on where or exactly what led me to this Q.

For instance, if I had a steady pressure of 8, but adjusted my APAP to 8-12, would I risk increasing my centrals?

A: NO

The S9 AutoSet and AirSense10 AutoSet/AutoSet 4Her with enhanced algorthim can distinguish between obstructive and central apnea, and respond differently to each

Older machines like S8 AutoSet, cannot do that and for this reason did not treat apnea above 10 to avoid pressure run away and trigger central apnea but continue to respond to snoring and flow limitation which are signs of obstructive apnea, not central apnea

Keep in mind the machine cannot tell whether you're awake or asleep, apnea scored while awake can be discarded

(11-18-2014, 08:55 PM)DocWils Wrote: In response to SurferDude, the machine can mistake a skipped breath or a swallow when awake as an event,

It remarkable what the machine can determine from merely measuring the air flow and sending pulses through it when somethings is determined to fall outside the parameters of the algorithm it's running under.

I have no problem believing that because we used the same principle in the oil patch when I was roughnecking to find out if there were any obstructions in a drill pipe before connecting it to the drill string. We would slap the palm of our hand over the open end of the pipe and listen for the echo. The echo was quite resounding when the pipe was clear but a dead thud type of sound would indicate that something was lodged (a rabbit, snake, beer can, etc.) in the pipe that might get pumped down to the drill bit orifices and cause a high mud pump pressure that would necessitate a round trip on the string.

These smart aleck CPAP machines do that with a fluttering pressure signal that reflects back how open the airways are. Amazing application of oil patch technology, what?

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.

(11-18-2014, 08:25 PM)TyroneShoes Wrote: For instance, if I had a steady pressure of 8, but adjusted my APAP to 8-12, would I risk increasing my centrals?

Yes, especially if you're new to CPAP therapy.

If you're going to get centrals because new to the therapy, you'll get them regardless whether you,re using constant pressure or variable pressure

When I first started CPAP, my AHI was made up of centrals/obstructive/unknown apnea and hyponea, and leak was all over the place but once I settled down, everything else settled down too and my sleep quality went up

Useful Links

INFORMATION ON APNEA BOARD FORUMS OR ON APNEABOARD.COM SHOULD NOT BE CONSIDERED AS MEDICAL ADVICE. ALWAYS SEEK THE ADVICE OF A PHYSICIAN BEFORE SEEKING TREATMENT FOR MEDICAL CONDITIONS, INCLUDING SLEEP APNEA. INFORMATION POSTED ON THE APNEA BOARD WEB SITE AND FORUMS ARE PERSONAL OPINION ONLY AND NOT NECESSARILY A STATEMENT OF FACT.